Vehicular lamp unit and vehicular lamp

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to a vehicular lamp unit and a vehicular lamp of so-called projector-type, and particularly relates to a vehicular lamp unit and a vehicular lamp provided with a shade that forms a cut-off line of a light distribution pattern.

2. Related Art

Conventionally, as one form of a vehicular lamp such as a headlamp, a so-called projector-type vehicular lamp is known. This projector-type vehicular lamp is structured to collect and reflect light from a light source disposed on an optical axis to the front towards the optical axis using a reflector, and to radiate the reflected light to the front of the lamp via a projection lens provided in front of the reflector.

It is common that, when such a projector-type lamp unit is used as a low-beam headlamp, a shade is provided between the projection lens and the light source, and a part of the reflected light from the reflector and a part of direct light from the light source are blocked by the shade, thereby forming a cut-off line of a light distribution pattern. Therefore, for instance, the light that is incident below the reflector and blocked by the shade becomes loss of light that does not contribute to the light distribution projected forward. Particularly, when a semiconductor light-emitting element is used as the light source, an amount of radiated light is likely to be insufficient.

Accordingly, there has been proposed a projector-type lamp unit provided with a main reflector having a first reflective surface that reflects direct light from a light source to the front towards an optical axis, and a sub-reflector including a shade mechanism having a second reflective surface disposed in between a convex lens (projection lens) and the light source and formed in a generally flat shape along an optical axis of the convex lens (for instance, Patent Document 1).

With the use of such a lamp unit, by reflecting a part of reflected light from the main reflector upward using the second reflective surface of the sub-reflector, it is possible to effectively utilize the light, which is blocked and thus not used, to perform beam radiation to the lower side of a cut-off line. <ul><li id="ul0001-0001" num="0008">[Patent Document 1] Japanese Patent Application Laid-Open (Kokai) No. JP-A-2006-107955</li></ul>

SUMMARY OF INVENTION

However, even when a part of the reflected light from the main reflector is reflected upward by the second reflective surface of the sub-reflector as in the above-described lamp unit, the light cannot be radiated at all above the cut-off line of the light distribution pattern. If the light is not radiated at all above the cut-off line, a forward visibility is not good, and it is hard to recognize an object on an opposite lane. Specifically, radiated light with such a level that the light does not give a glare to a vehicle on the opposite lane is necessary for improving the forward visibility also above a cut-off line in a low-beam light distribution pattern.

Accordingly, one or more embodiments of the present invention provide a vehicular lamp unit and a vehicular lamp capable of improving a forward visibility by radiating light also above a cut-off line of a light distribution pattern.

One or more embodiments of the present invention relate to a vehicular lamp unit having a projection lens disposed on an optical axis extending in a vehicular longitudinal direction, a light source disposed rearward of a rear side focal point of the projection lens, a reflector reflecting direct light from the light source to the front towards the optical axis, and a shade disposed between the projection lens and the light source and blocking a part of reflected light from the reflector and a part of the direct light from the light source to form a cut-off line of a light distribution pattern. The vehicular lamp unit is characterized by including: a first reflective surface that is formed on a tip portion of the reflector and reflects a part of the direct light from the light source downward to the front of the shade; and a second reflective surface that is formed on the front of the shade and below the rear side focal point of the projection lens, and reflects reflected light from the first reflective surface towards the projection lens. In the vehicular lamp unit, the first reflective surface is formed in a shape of ellipsoidal reflective surface having a vertical cross-section that is generally ellipsoidal in shape, and the second reflective surface is formed in a generally plate shape having a linear vertical cross-section.

With the use of the vehicular lamp unit structured as above, after a part of the direct light from the light source is reflected by the first reflective surface having a shape of ellipsoidal reflective surface formed on the tip portion of the reflector, the reflected light is further reflected towards the projection lens by the second reflective surface having a generally plate shape formed on the front of the shade and below the rear side focal point of the projection lens. Subsequently, the light incident on the projection lens from the second reflective surface is emitted as upward directed radiated light, which enables to radiate above the cut-off line of the light distribution pattern.

In one or more embodiments, it is preferable that in the vehicular lamp unit structured as above, the first reflective surface include: a first reflective surface for right-side light distribution that reflects light from the light source towards the second reflective surface for right-side light distribution formed on the front of the shade for right-side light distribution that forms a cut-off line of a light distribution pattern for right-side light distribution and below the rear side focal point of the projection lens; and a first reflective surface for left-side light distribution that reflects light from the light source towards the second reflective surface for left-side light distribution formed on the front of the shade for left-side light distribution that forms a cut-off line of a light distribution pattern for left-side light distribution and below the rear side focal point of the projection lens.

With the use of the vehicular lamp unit having such a structure, because the reflector can be used for both the vehicular lamp unit for right-side light distribution and the vehicular lamp unit for left-side light distribution, the number of parts can be reduced.

Further, in one or more embodiments of the present invention, the vehicular lamp is characterized in that an entire light distribution pattern is formed by combining a light distribution from the vehicular lamp unit structured as above and a light distribution from another vehicular lamp unit having a light collecting power higher than a light collecting power of the above vehicular lamp unit.

With the use of the vehicular lamp structured as above, when light distributions from a plurality of lamp units are combined to form an entire light distribution pattern, by forming the first reflective surface and the second reflective surface on the reflector and the shade, respectively, in a diffusing-type lamp unit having a light collecting power lower than that of another vehicular lamp unit, it is possible to easily radiate above the cut-off line of the light distribution pattern in a diffused manner along a vehicle width direction.

With the use of the vehicular lamp unit according to one or more embodiments of the present invention, the light incident on the projection lens from the second reflective surface after being reflected by the first reflective surface is emitted as the upward directed radiated light, which enables to radiate above the cut-off line of the light distribution pattern. Accordingly, it is possible to improve the forward visibility.

Other aspects and advantages of the invention will be apparent from the following description, the drawings and the claims.

BRIEF DESCRIPTION OF DRAWINGS

<figref idrefs="DRAWINGS">FIG. 1</figref> is a horizontal cross sectional view of a vehicular lamp according to one or more embodiments of the present invention.

<figref idrefs="DRAWINGS">FIG. 2</figref> is an arrow view along the line II-II in <figref idrefs="DRAWINGS">FIG. 1</figref>.

<figref idrefs="DRAWINGS">FIG. 3</figref> is a longitudinal sectional view that explains a basic structure of a lamp unit shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 4</figref> is a longitudinal sectional view that explains the basic structure of the lamp unit shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 5</figref> is a lower perspective view of a reflector shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 6</figref> is an upper perspective view of a shade shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 7</figref> is a view that shows, in a perspective manner, a low-beam light distribution pattern formed on a virtual vertical screen disposed at a position 25 meters (“m”) ahead of the lamp by light radiated from the lamp unit shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

<figref idrefs="DRAWINGS">FIG. 8</figref> is an upper perspective view of a shade for right-side light distribution that forms a cut-off line of a light distribution pattern for right-side light distribution.

DETAILED DESCRIPTION

Hereafter, embodiments of a vehicular lamp unit and a vehicular lamp according to the present invention will be described in detail with reference to accompanying drawings.

<figref idrefs="DRAWINGS">FIG. 1</figref> is a horizontal cross sectional view of a vehicular lamp according to one or more embodiments of the present invention.

A vehicular lamp <b>100</b> is a low-beam headlamp, and is structured such that, in a lamp chamber formed of a plain translucent cover <b>11</b> and a lamp body <b>13</b>, a plurality of lamp units (two are shown) are housed side-by-side. The plurality of lamp units are formed of a lamp unit (vehicular lamp unit) <b>20</b> having a low light collecting power and another lamp unit (another vehicular lamp unit) <b>40</b> having a light collecting power higher than that of the lamp unit <b>20</b>.

These lamp units <b>20</b>, <b>40</b> are supported in the lamp body <b>13</b> via a frame (not shown), and the frame is supported in the lamp body <b>13</b> via an aiming mechanism (not shown).

The aiming mechanism is a mechanism for finely adjusting attachment positions and attachment angles of these lamp units <b>20</b>, <b>40</b>. The aiming mechanism is designed such that when the aiming adjustment is completed, a lens central axis Ax of each of the lamp units <b>20</b>, <b>40</b> extends in a downward direction by about 0.5 to 0.6 degrees relative to a vehicular longitudinal direction.

As will be described later, the lamp unit <b>20</b> forms a diffusion zone formation pattern WZ having horizontal and oblique cut-off lines on an upper end edge thereof. The lamp unit <b>40</b> forms a hot zone formation pattern HZ having horizontal and oblique cut-off lines on an upper end edge thereof.

Specifically, a low-beam light distribution pattern PL formed by the vehicular lamp <b>100</b> is designed to be formed as a combined light distribution pattern of the diffusion zone formation pattern WZ and the hot zone formation pattern HZ formed by these two lamp units <b>20</b>, <b>40</b> (refer to <figref idrefs="DRAWINGS">FIG. 7</figref>).

These lamp units <b>20</b>, <b>40</b>, which serve as low-beam light distribution pattern forming units are structured as projector-type lamp units each formed of a light source and a projection lens provided on a front side of the light source, as will be described later.

Hereinafter, a structure of each of the lamp units <b>20</b>, <b>40</b> will be described.

Firstly, a structure of the lamp unit <b>20</b> will be described.

<figref idrefs="DRAWINGS">FIG. 2</figref> is an arrow view along the line II-II in <figref idrefs="DRAWINGS">FIG. 1</figref>, <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref> are longitudinal sectional views that explain a basic structure of a lamp unit shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, <figref idrefs="DRAWINGS">FIG. 5</figref> is a lower perspective view of a reflector shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, <figref idrefs="DRAWINGS">FIG. 6</figref> is an upper perspective view of a shade shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, and <figref idrefs="DRAWINGS">FIG. 7</figref> is a view that shows, in a perspective manner, a low-beam light distribution pattern formed on a virtual vertical screen disposed at a position 25 meters (“m”) ahead of the lamp by light radiated from the lamp unit shown in <figref idrefs="DRAWINGS">FIG. 2</figref>.

As shown in <figref idrefs="DRAWINGS">FIG. 2</figref>, the lamp unit <b>20</b> includes a projection lens <b>35</b> disposed on an optical axis Ax extending in a vehicular longitudinal direction; an LED (light-emitting diode) <b>25</b> as a light source disposed rearward of a rear side focal point F of the projection lens <b>35</b>; a reflector <b>27</b> that reflects direct light from the LED <b>25</b> to the front towards the optical axis Ax; and a shade <b>29</b>L that is disposed between the projection lens <b>35</b> and the LED <b>25</b>, and forms a cut-off line of a light distribution pattern by blocking a part of reflected light from the reflector <b>27</b> and a part of the direct light from the LED <b>25</b>.

The LED <b>25</b> is a white light-emitting diode having a single light-emitting chip <b>25</b><i>a </i>whose size is about 1 millimeter (“mm”) square, for instance. The LED <b>25</b> is disposed rearward of the rear side focal point F of the projection lens <b>35</b>, and directed upward in the vertical direction on the optical axis Ax in the state where the LED <b>25</b> is supported by a substrate <b>33</b>.

As shown in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref>, the reflector <b>27</b> is a generally dome-shaped member provided on an upper side of the LED <b>25</b>, and has a reflective surface <b>27</b><i>a </i>that collects and reflects light L<b>1</b> from the LED <b>25</b> to the front towards the optical axis Ax.

This reflective surface <b>27</b><i>a </i>is formed in a shape of an ellipsoidal reflective surface in which the optical axis Ax is set as a central axis. Specifically, this reflective surface <b>27</b><i>a </i>has a vertical cross-section including the optical axis Ax that is set to be a generally ellipsoidal shape, and an eccentricity thereof is set to gradually increase from the vertical cross-section to a horizontal cross-section.

However, rear side vertexes of ellipses forming the respective cross-sections are set at the same position, and the LED <b>25</b> is disposed on a first focal point of the ellipse forming the vertical cross-section of this reflective surface <b>27</b><i>a</i>. Accordingly, it is designed such that the reflective surface <b>27</b><i>a </i>collects and reflects the light L<b>1</b> from the LED <b>25</b> to the front towards the optical axis Ax, and, at that time, the light is generally converged on a second focal point of the ellipse on the vertical cross-section including the optical axis Ax.

Further, a first reflective surface that reflects a part of the direct light from the LED <b>25</b> downward to the front of the shade <b>29</b>L is formed on a tip portion of the reflector <b>27</b>, as shown in <figref idrefs="DRAWINGS">FIG. 5</figref>.

The first reflective surface is formed further on a tip portion of an effective reflective surface of the reflective surface <b>27</b><i>a </i>of the reflector <b>27</b>. The first reflective surface includes a first reflective surface <b>31</b> for left-side light distribution that reflects light from the LED <b>25</b> towards a second reflective surface <b>38</b> for left-side light distribution formed on the front of the shade <b>29</b>L for left-side light distribution that forms a cut-off line of a light distribution pattern for left-side light distribution (refer to <figref idrefs="DRAWINGS">FIG. 6</figref>) and below the rear side focal point F of the projection lens <b>35</b>, and a first reflective surface <b>32</b> for right-side light distribution that reflects light from the LED <b>25</b> towards a second reflective surface <b>39</b> for right-side light distribution formed on the front of a shade <b>29</b>R for right-side light distribution that forms a cut-off line of a light distribution pattern for right-side light distribution (refer to <figref idrefs="DRAWINGS">FIG. 8</figref>) and below the rear side focal point F of the projection lens <b>35</b>.

The first reflective surface <b>31</b> for left-side light distribution is formed in a shape of an ellipsoidal reflective surface having a vertical cross-section that is generally ellipsoidal in shape and whose first focal point and second focal point are respectively set to the LED <b>25</b> and the second reflective surface <b>38</b> for left-side light distribution. Further, the second reflective surface <b>38</b> for left-side light distribution is formed in a generally flat shape having a linear vertical cross-section.

Besides, each of these first reflective surface <b>31</b> for left-side light distribution and second reflective surface <b>38</b> for left-side light distribution is laterally divided into two. Further, it is structured such that reflected light L<b>3</b><i>a </i>reflected by a first reflective surface <b>31</b><i>a </i>for left-side light distribution and a second reflective surface <b>38</b><i>a </i>for left-side light distribution radiates “H-4R” on H line in a low-beam left-side light distribution pattern with a predetermined amount of light, and reflected light L<b>3</b><i>b </i>reflected by a first reflective surface <b>31</b><i>b </i>for left-side light distribution and a second reflective surface <b>38</b><i>b </i>for left-side light distribution radiates “H-8R” on the H line in the pattern with a predetermined amount of light, which is a requirement imposed by a European regulation (ECE R112) (refer to <figref idrefs="DRAWINGS">FIG. 7</figref>).

Similar to the first reflective surface <b>31</b> for left-side light distribution, the first reflective surface <b>32</b> for right-side right distribution is formed in a shape of an ellipsoidal reflective surface having a vertical cross-section that is generally ellipsoidal in shape and whose first focal point and second focal point are respectively set to the LED <b>25</b> and the second reflective surface <b>39</b> for right-side light distribution. Further, the second reflective surface <b>39</b> for right-side light distribution is also formed in a generally flat shape having a linear vertical cross-section.

Each of these first reflective surface <b>32</b> for right-side light distribution and second reflective surface <b>39</b> for right-side light distribution is also laterally divided into two.

Further, it is structured such that reflected light L<b>3</b><i>a </i>reflected by a first reflective surface <b>32</b><i>a </i>for right-side light distribution and a second reflective surface <b>39</b><i>a </i>for right-side light distribution radiates “H-4L” on H line in a low-beam right-side light distribution pattern with a predetermined amount of light, and reflected light L<b>3</b><i>b </i>reflected by a first reflective surface <b>32</b><i>b </i>for right-side light distribution and a second reflective surface <b>39</b><i>b </i>for right-side light distribution radiates “H-8L” on the H line in the pattern with a predetermined amount of light.

The projection lens <b>35</b> is formed of a planoconvex lens, a front side surface of which is a convex surface and a rear side surface of which is a flat surface. This projection lens <b>35</b> is disposed on the optical axis Ax so that the rear side focal point F thereof is positioned on a second focal point of the reflective surface <b>27</b><i>a </i>of the reflector <b>27</b>, as shown in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref>. Accordingly, an image on a focal plane including the rear side focal point F is set to be projected forward as an inverted image.

In one or more embodiments of the present invention, the shade <b>29</b>L has a shape of a block that also serves as a supporting frame of the projection lens <b>35</b>, and the shade <b>29</b>L is disposed between the projection lens <b>35</b> and the LED <b>25</b>, as shown in <figref idrefs="DRAWINGS">FIG. 2</figref> and <figref idrefs="DRAWINGS">FIG. 6</figref>. Further, the shade <b>29</b>L has a front end edge <b>29</b><i>c </i>that positions in the vicinity of the rear side focal point F of the projection lens <b>35</b> and blocks a part of the reflected light from the reflector <b>27</b> to form a cut-off line of the left-side light distribution pattern, and the shade <b>29</b>L has an upper surface <b>29</b><i>a </i>that extends rearward from the front end edge <b>29</b><i>c </i>and reflects a part of the reflected light from the reflector <b>27</b> on the upper side. A light control surface <b>36</b> to which reflective surface treatment is applied is formed on the upper surface <b>29</b><i>a. </i>

Specifically, the shade <b>29</b>L is designed such that, by reflecting a part of the reflected light from the reflector <b>27</b> upward using the light control surface <b>36</b>, most of the light to be emitted upward from the projection lens <b>35</b> is converted into the light L<b>2</b> emitted downward from the projection lens <b>35</b>, thereby enhancing a luminous flux utilization factor of the light emitted from the LED <b>25</b>, as shown in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref>.

Specifically, the light control surface <b>36</b> is formed of a horizontal cut-off formation surface <b>37</b><i>a </i>extending horizontally in the right direction of a vehicle generally from the optical axis Ax (in the left direction in <figref idrefs="DRAWINGS">FIG. 6</figref>), an oblique cut-off formation surface <b>37</b><i>b </i>extending obliquely downward by 15° in the left direction generally from the optical axis Ax (in the right direction in <figref idrefs="DRAWINGS">FIG. 6</figref>), and a horizontal cut-off formation surface <b>37</b><i>c </i>extending horizontally in the left direction from the oblique cut-off formation surface <b>37</b><i>b </i>(in the right direction in <figref idrefs="DRAWINGS">FIG. 6</figref>). The front end edge (namely, an edge line between the light control surface <b>36</b> and a front end surface <b>29</b><i>b </i>of the shade <b>29</b>L) <b>29</b><i>c </i>is formed so as to pass through the rear side focal point F of the projection lens <b>35</b>.

Further, of the light emitted from the LED <b>25</b>, a part of the light reflected by the reflective surface <b>27</b><i>a </i>of the reflector <b>27</b> is incident on the light control surface <b>36</b> of the shade <b>29</b>L, and the remainder of the light is incident directly on the projection lens <b>35</b>. At that time, the light incident on the light control surface <b>36</b> is incident on the projection lens <b>35</b> by being reflected upward by the light control surface <b>36</b>, and the light is emitted as the downward directed light L<b>2</b> from the projection lens <b>35</b>.

Note that the front end edge <b>29</b><i>c </i>of the shade <b>29</b>L is formed in a curved shape in which lateral ends thereof protrude forward in a plane view so as to correspond to a field curvature of the projection lens <b>35</b>. The curved front end edge <b>29</b><i>c </i>coincides with a focal group of the projection lens <b>35</b>. Specifically, the front end edge <b>29</b><i>c </i>of the shade <b>29</b>L is formed along the focal group of the projection lens <b>35</b>, and a shape of the front end edge <b>29</b><i>c </i>directly corresponds to a shape of the cut-off line.

Further, the aforementioned second reflective surface <b>38</b> for left-side light distribution is integrally formed towards the left direction of the vehicle (on the front of the horizontal cut-off formation surface <b>37</b><i>c</i>) in the vicinity of the front end edge <b>29</b><i>c </i>of the shade <b>29</b>L.

Specifically, in the lamp unit <b>20</b> of one or more embodiments of the present embodiment, a part of the direct light from the LED <b>25</b> is reflected by the first reflective surface <b>31</b> having a shape of an ellipsoidal reflective surface formed on the tip portion of the reflector <b>27</b>. Then, the light is reflected towards the projection lens <b>35</b> by the second reflective surface <b>38</b> having a shape of a generally flat surface formed on the front of the shade <b>29</b>L and below the rear side focal point F of the projection lens <b>35</b>, as shown in <figref idrefs="DRAWINGS">FIG. 3</figref> and <figref idrefs="DRAWINGS">FIG. 4</figref>. Subsequently, the light incident on the projection lens <b>35</b> from the second reflective surface <b>38</b> is emitted as the upward directed radiated light L<b>3</b><i>b</i>, which radiates above a cut-off line CL<b>3</b> of the low-beam light distribution pattern PL.

Next, the lamp unit <b>40</b> will be described.

As shown in <figref idrefs="DRAWINGS">FIG. 1</figref>, the lamp unit <b>40</b> includes a light-emitting diode as a light source (not shown), a reflector <b>47</b>, and a projection lens <b>45</b>. The light-emitting diode has the same structure as that of the LED <b>25</b> of the lamp unit <b>20</b>, and is disposed on an optical axis Ax by being directed upward in the vertical direction.

The reflector <b>47</b> is a generally dome-shaped member provided on an upper side of the light-emitting diode. Further, the reflector <b>47</b> has a reflective surface having a shape of an ellipsoidal reflective surface that collects and reflects light from the light-emitting diode to the front, with high light collecting power compared to that of the reflective surface <b>27</b><i>a </i>of the reflector <b>27</b>.

The projection lens <b>45</b> is formed of a planoconvex lens that has a convex front side surface and a flat rear side surface. The projection lens <b>45</b> is disposed on the optical axis Ax so that a rear side focal point of the projection lens <b>45</b> is positioned on a second focal point of the reflective surface of the reflector <b>47</b>, and, accordingly, an image on a focal plane including the rear side focal point is set to be projected forward as an inverted image. Note that the projection lens <b>45</b> uses a lens whose diameter is larger than that of the projection lens <b>35</b> of the lamp unit <b>20</b> so that the radiated light from the lamp unit <b>40</b> reaches further distances.

Further, as shown in <figref idrefs="DRAWINGS">FIG. 7</figref>, the diffusion zone formation pattern WZ formed by the lamp unit <b>20</b> is a light distribution pattern for left-hand traffic having a cut-off line CL<b>1</b> of a vehicle's own lane side and a cut-off line CL<b>3</b> of an opposite lane side, which extend in a horizontal direction, and an oblique cut-off line CL<b>2</b>, on an upper end edge of the diffusion zone formation pattern WZ.

Further, a light distribution pattern <b>4</b>SZ is a light distribution pattern in which the reflected light L<b>3</b><i>a </i>reflected by the first reflective surface <b>31</b><i>a </i>for left-side light distribution and the second reflective surface <b>38</b><i>a </i>for left-side light distribution radiates “H-4R” on the H line in the low-beam left-side light distribution pattern with a predetermined amount of light. Further, a light distribution pattern <b>8</b>SZ is a light distribution pattern in which the reflected light L<b>3</b><i>b </i>reflected by the first reflective surface <b>31</b><i>b </i>for left-side light distribution and the second reflective surface <b>38</b><i>b </i>for left-side light distribution radiates “H-8R” on the H line in the low-beam left-side light distribution pattern with a predetermined amount of light.

Further, the hot zone formation pattern HZ of the lamp unit <b>40</b> is formed by the lamp unit <b>40</b> so as to overlap with the diffusion zone formation pattern WZ, and is a hot zone formation pattern in which a light collecting power is higher than that in the diffusion zone formation pattern WZ.

Accordingly, the diffusion zone formation pattern WZ, the hot zone formation pattern HZ, and the light distribution patterns <b>4</b>SZ and <b>8</b>SZ overlap in the illustrated manner, thereby forming the low-beam light distribution pattern PL of the vehicular lamp <b>100</b> as a combined light distribution pattern.

Specifically, with the use of the vehicular lamp unit <b>20</b> of the vehicular lamp <b>100</b> according to one or more embodiments of the present invention, a part of the direct light from the LED <b>25</b> is reflected by the first reflective surfaces <b>31</b><i>a</i>, <b>31</b><i>b </i>formed on the tip portion of the reflector <b>27</b>, and the light is then reflected towards the projection lens <b>35</b> by the second reflective surfaces <b>38</b><i>a</i>, <b>38</b><i>b </i>formed on the front of the shade <b>29</b>L and below the rear side focal point F of the projection lens <b>35</b>. Subsequently, the light incident on the projection lens <b>35</b> from the second reflective surfaces <b>38</b><i>a</i>, <b>38</b><i>b </i>is emitted as the upward directed radiated lights L<b>3</b><i>a</i>, L<b>3</b><i>b</i>, which enables radiation above the cut-off line CL<b>3</b> of the opposite lane side of the low-beam light distribution pattern PL.

Therefore, the vehicular lamp unit <b>20</b> can radiate the predetermined amount of reflected light, with such a level that the light does not give a glare to a vehicle on the opposite lane, also onto the above the cut-off line CL<b>3</b> of the opposite lane side, which improves the forward visibility.

Further, when the first reflective surfaces <b>31</b><i>a</i>, <b>31</b><i>b </i>are formed as reflective surfaces each having a shape of an ellipsoidal reflective surface as in the vehicular lamp unit <b>20</b> of one or more embodiments of the present invention, it is possible to improve a design flexibility regarding the light distribution pattern of the radiated light and the amount of radiated light that radiates above the cut-off line of the low-beam light distribution pattern PL. Further, when the second reflective surfaces <b>38</b><i>a</i>, <b>38</b><i>b </i>are formed as reflective surfaces each having a generally flat shape as in the vehicular lamp unit <b>20</b> of one or more embodiments of the present invention, it is possible to easily obtain diffused light.

Further, because the first reflective surfaces <b>31</b>, <b>32</b> of one or more embodiments of the present invention are integrally formed further on the tip side of the effective reflective surface of the reflective surface <b>27</b><i>a </i>of the reflector <b>27</b>, it is possible to effectively utilize the reflector <b>27</b> without influencing the light L<b>1</b> of a main light distribution, and to easily manufacture the reflector <b>27</b>.

Further, the first reflective surfaces <b>31</b>, <b>32</b> are positioned further on the LED <b>25</b> side of the rear side focal point F of the projection lens <b>35</b> and are formed close to the LED <b>25</b>, so that sizes of the first reflective surfaces <b>31</b>, <b>32</b> can be reduced. Note that a light source image of the reflected light from the first reflective surfaces <b>31</b>, <b>32</b> close to the LED <b>25</b> becomes large, which enables radiation of weak light over a wide range to the above the H line.

Further, the lamp unit <b>20</b> of one or more embodiments of the present invention is used as a diffusing-type lamp unit having the lowest light collecting power in the vehicular lamp <b>100</b> that combines a light distribution from another lamp unit <b>40</b> having a light collecting power higher than that of the lamp unit <b>20</b> to form the entire low-beam light distribution pattern PL.

Accordingly, in cases that the vehicular lamp <b>100</b> combines the light distributions from the plurality of lamp units <b>20</b>, <b>40</b> to form the entire low-beam light distribution pattern PL, by forming the first reflective surface <b>31</b> and the second reflective surface <b>38</b> on the reflector <b>27</b> and the shade <b>29</b>L, respectively, in the diffusing-type lamp unit <b>20</b> having a light collecting power lower than that of another lamp unit <b>40</b>, it is possible to easily radiate above the cut-off line CL<b>3</b> of the low-beam light distribution pattern PL in a diffused manner along a vehicle width direction.

<figref idrefs="DRAWINGS">FIG. 8</figref> is an upper perspective view of the shade <b>29</b>R for right-side light distribution that forms a cut-off line of a light distribution pattern for right-side light distribution.

Similar to the shade <b>29</b>L of the aforementioned embodiments, the shade <b>29</b>R has a front end edge <b>29</b><i>c </i>that positions in the vicinity of the rear side focal point F of the projection lens <b>35</b> and blocks a part of the reflected light from the reflector <b>27</b> to form the cut-off line of the right-side light distribution pattern, and has an upper surface <b>29</b><i>a </i>that extends rearward from the front end edge <b>29</b><i>c </i>and reflects a part of the reflected light from the reflector <b>27</b> on the upper side. A light control surface <b>51</b> to which reflective surface treatment is applied is formed on the upper surface <b>29</b><i>a. </i>

The light control surface <b>51</b> is formed of a horizontal cut-off formation surface <b>51</b><i>a </i>extending horizontally in the right direction of the vehicle generally from the optical axis Ax (in the left direction in <figref idrefs="DRAWINGS">FIG. 8</figref>), an oblique cut-off formation surface <b>51</b><i>b </i>extending obliquely upward by 15° in the left direction generally from the optical axis Ax (in the right direction in <figref idrefs="DRAWINGS">FIG. 8</figref>), and a horizontal cut-off formation surface <b>51</b><i>c </i>extending horizontally in the left direction from the oblique cut-off formation surface <b>51</b><i>b </i>(in the right direction in <figref idrefs="DRAWINGS">FIG. 8</figref>). The front end edge (namely, an edge line between the light control surface <b>51</b> and a front end surface <b>29</b><i>b </i>of the shade <b>29</b>R) <b>29</b><i>c </i>is formed so as to pass through the rear side focal point F of the projection lens <b>35</b>.

Further, of the light emitted from the LED <b>25</b>, a part of the light reflected by the reflective surface <b>27</b><i>a </i>of the reflector <b>27</b> is incident on the light control surface <b>51</b> of the shade <b>29</b>R, and the remainder of the light is incident directly on the projection lens <b>35</b>. At that time, the light incident on the light control surface <b>51</b> is incident on the projection lens <b>35</b> by being reflected upward by the light control surface <b>51</b>, and the light is emitted as the downward directed light L<b>2</b> from the projection lens <b>35</b>.

Further, the second reflective surface <b>39</b> for right-side light distribution is integrally formed towards the right direction of the vehicle (on the front of the horizontal cut-off formation surface <b>51</b><i>a</i>) in the vicinity of the front end edge <b>29</b><i>c </i>of the shade <b>29</b>R.

Therefore, only by using the shade <b>29</b>R instead of the shade <b>29</b>L in the lamp unit <b>20</b> of the aforementioned embodiments, it is possible to change the lamp unit <b>20</b> for left-side light distribution into a lamp unit for right-side light distribution.

At this time, the aforementioned reflector <b>27</b> is previously provided with the first reflective surface <b>31</b> for left-side light distribution and the first reflective surface <b>32</b> for right-side light distribution, so that the reflector <b>27</b> can be used for both the lamp unit <b>20</b> for right-side light distribution and the lamp unit for left-side light distribution. Therefore, it is also possible to reduce the manufacturing cost by reducing the number of parts at the time of manufacturing the lamp unit <b>20</b> for right-side light distribution and the lamp unit for left-side light distribution.

The vehicular lamp unit and the vehicular lamp of the present invention may be modified in structure from the aforementioned embodiments, and various embodiments may be adopted within the spirit of the present invention.

For instance, although the vehicular lamp <b>100</b> of the aforementioned embodiments is structured such that the plurality of lamp units are housed side-by-side in the lamp chamber, one or more embodiments of the present invention may employ a single lamp unit. Further, the light source is described as a semiconductor light-emitting element such as a light-emitting diode, however, a discharge bulb such as a metal halide bulb and a halogen bulb may also be used.

While description has been made in connection with exemplary embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modification may be made therein without departing from the present invention. It is aimed, therefore, to cover in the appended claims all such changes and modifications falling within the true spirit and scope of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

<ul><li id="ul0002-0001" num="0000"><ul><li id="ul0003-0001" num="0083"><b>20</b> Lamp Unit (Vehicular Lamp Unit)</li><li id="ul0003-0002" num="0084"><b>25</b> Led (Light Source)</li><li id="ul0003-0003" num="0085"><b>27</b> Reflector</li><li id="ul0003-0004" num="0086"><b>29</b>L Shade</li><li id="ul0003-0005" num="0087"><b>29</b><i>a </i>Upper Surface</li><li id="ul0003-0006" num="0088"><b>29</b><i>c </i>Front End Edge</li><li id="ul0003-0007" num="0089"><b>31</b> First Reflective Surface for Left-Side Light Distribution (First Reflective Surface)</li><li id="ul0003-0008" num="0090"><b>32</b> First Reflective Surface for Right-Side Light Distribution (First Reflective Surface)</li><li id="ul0003-0009" num="0091"><b>35</b> Projection Lens</li><li id="ul0003-0010" num="0092"><b>36</b> Light Control Surface</li><li id="ul0003-0011" num="0093"><b>38</b> Second Reflective Surface for Left-Side Light Distribution (Second Reflective Surface)</li><li id="ul0003-0012" num="0094"><b>39</b> Second Reflective Surface for Right-Side Light Distribution (Second Reflective Surface)</li><li id="ul0003-0013" num="0095"><b>40</b> Lamp Unit (Another Vehicular Lamp Unit)</li><li id="ul0003-0014" num="0096"><b>100</b> Vehicular Lamp</li><li id="ul0003-0015" num="0097">Ax Optical Axis</li><li id="ul0003-0016" num="0098">CL Cut-Off Line</li><li id="ul0003-0017" num="0099">CL<b>1</b> Cut-Off Line Of Vehicle'S Own Lane Side</li><li id="ul0003-0018" num="0100">CL<b>2</b> Oblique Cut-Off Line</li><li id="ul0003-0019" num="0101">CL<b>3</b> Cut-Off Line Of Opposite Lane Side</li><li id="ul0003-0020" num="0102">F Rear Side Focal Point</li></ul></li></ul>